Can DM500HD receive Dolby sound channels



My Satellite Setup
db7000, steerable dish
My Location
York, England
I have a DM500HD connected to a Sony DN1050 amp. I watch FTA French TV on Eutelsat 5.0W [on 11591 V 20000 QPSK]. Up till April all was OK. Since then I get both Video and Audio on France 3, but Video only for France 2 and France 4. In the About menu, Service, PIDs, the Sound PID shows N/A for Fr2 and Fr4, and 0x00e6 for Fr3.
I have found this note:
and this thread:
Just Sharing This - fransat fta channels from 5 april
which says the problem is with Dolby encoded sound (which ties in with the Fr2/Fr3/Fr4 effect), and mentions AC3 downmix (OFF) and HDMI cables.
But my problem seems to be that I get no Sound PID, right back in the Tuner, rather than in the subsequent audio format decoding.
Do I need a more modern DB ?